Displaying publications 61 - 80 of 453 in total

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  1. Jeevananthan C, Muhamad NA, Jaafar MH, Hod R, Ab Ghani RM, Md Isa Z, et al.
    BMJ Open, 2020 11 04;10(11):e039623.
    PMID: 33148753 DOI: 10.1136/bmjopen-2020-039623
    INTRODUCTION: The current global pandemic of the virus that emerged from Hubei province in China has caused coronavirus disease in 2019 (COVID-19), which has affected a total number of 900 036 people globally, involving 206 countries and resulted in a cumulative of 45 693 deaths worldwide as of 3 April 2020. The mode of transmission is identified through airdrops from patients' body fluids such as during sneezing, coughing and talking. However, the relative importance of environmental effects in the transmission of the virus has not been vastly studied. In addition, the role of temperature and humidity in air-borne transmission of infection is presently still unclear. This study aims to identify the effect of temperature, humidity and air quality in the transmission of SARS-CoV-2.

    METHODS AND ANALYSIS: We will systematically conduct a comprehensive literature search using various databases including PubMed, EMBASE, Scopus, CENTRAL and Google Scholar to identify potential studies. The search will be performed for any eligible articles from the earliest published articles up to latest available studies in 2020. We will include all the observational studies such as cohort case-control and cross-sectional studies that explains or measures the effects of temperature and/or humidity and/or air quality and/or anthropic activities that is associated with SARS-CoV-2. Study selection and reporting will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and Meta-Analysis of Observational Studies in Epidemiology guideline. All data will be extracted using a standardised data extraction form and quality of the studies will be assessed using the Newcastle-Ottawa Scale guideline. Descriptive and meta-analysis will be performed using a random effect model in Review Manager File.

    ETHICS AND DISSEMINATION: No primary data will be collected, and thus no formal ethical approval is required. The results will be disseminated through a peer-reviewed publication and conference presentation.

    PROSPERO REGISTRATION NUMBER: CRD42020176756.

    Matched MeSH terms: Air Pollution*; Air Pollution, Indoor
  2. Nur Azfahani Ahmad, Zuraihana Ahmad Zawawi, Nazhatulzalkis Jamaludin, Khairulliza Ahmad Salleh
    Jurnal Inovasi Malaysia, 2019;2(2):55-70.
    MyJurnal
    A 1984 World Health Organization (WHO) Committee report highlighted that up to 30 per cent of buildings may have to face problems related to Indoor Air Quality (IAQ). Insufficient ventilation will lead to stagnant air and can cause stuffiness in buildings. This will then leads to a bigger problem, known as the Sick Building Syndrome (SBS). It is important to note that sick building syndrome may cause various illnesses including allergies, acute respiration problem, feeling of discomfort and other psychological impacts. The “Ventilation Flow Evaluation System for Sustainable Housing Development” is a PC-based database tool developed to access and measure ventilation flow in a new or remodelled building in order to prevent or mitigate this problem. The purpose of the system is to provide resources for building designers in solving Indoor Air Quality (IAQ) issues especially related to ventilation flow based on regulations provided in Malaysian Standard (MS 1525). The system will allow readily building plan to be measured and analysed based on ventilation data collected at site, in order to allow buildings to obtain healthy and sufficient air for breathing and comfort purposes. The system will also recommend suitable layout plan in the building to meet the ventilation purposes, namely cross-ventilation and stack-effect ventilation.
    Matched MeSH terms: Air Conditioning; Air Pollution, Indoor; Air Filters
  3. Li L, Li Q, Huang L, Wang Q, Zhu A, Xu J, et al.
    Sci Total Environ, 2020 Aug 25;732:139282.
    PMID: 32413621 DOI: 10.1016/j.scitotenv.2020.139282
    The outbreak of COVID-19 has spreaded rapidly across the world. To control the rapid dispersion of the virus, China has imposed national lockdown policies to practise social distancing. This has led to reduced human activities and hence primary air pollutant emissions, which caused improvement of air quality as a side-product. To investigate the air quality changes during the COVID-19 lockdown over the YRD Region, we apply the WRF-CAMx modelling system together with monitoring data to investigate the impact of human activity pattern changes on air quality. Results show that human activities were lowered significantly during the period: industrial operations, VKT, constructions in operation, etc. were significantly reduced, leading to lowered SO2, NOx, PM2.5 and VOCs emissions by approximately 16-26%, 29-47%, 27-46% and 37-57% during the Level I and Level II response periods respectively. These emission reduction has played a significant role in the improvement of air quality. Concentrations of PM2.5, NO2 and SO2 decreased by 31.8%, 45.1% and 20.4% during the Level I period; and 33.2%, 27.2% and 7.6% during the Level II period compared with 2019. However, ozone did not show any reduction and increased greatly. Our results also show that even during the lockdown, with primary emissions reduction of 15%-61%, the daily average PM2.5 concentrations range between 15 and 79 μg m-3, which shows that background and residual pollutions are still high. Source apportionment results indicate that the residual pollution of PM2.5 comes from industry (32.2-61.1%), mobile (3.9-8.1%), dust (2.6-7.7%), residential sources (2.1-28.5%) in YRD and 14.0-28.6% contribution from long-range transport coming from northern China. This indicates that in spite of the extreme reductions in primary emissions, it cannot fully tackle the current air pollution. Re-organisation of the energy and industrial strategy together with trans-regional joint-control for a full long-term air pollution plan need to be further taken into account.
    Matched MeSH terms: Air Pollutants; Air Pollution*
  4. Ahmad Sayuti Zainal Abidin, Leman, A.M., Nor Mohd Razif Noraini
    MyJurnal
    This study was done to investigate the background level on microbiological indoor air pollutants in new constructed 8 stories buildings (2 level of Hostel facilities, 3 level of Training Room level, 2 level of Offices and 1 Exhibition Halls and Rooms) in Bandar Baru Bangi, Selangor. The offices and exhibition hall are carpeted furnished. All these spaces were using centralized air conditioning system. Airborne microbes’ concentrations were determined by using a single stage impactor (Biosampler) as per requirement of National Institute of Occupational Safety and Health NIOSH method NIOSH Manual Analytical Method MAM 0800. Mean concentration of total bacteria detected is 1351 CFU/m3 and it was found significantly higher compared to maximum exposure limit 500 CFU/m3 in office room. The mean concentration of total fungi in the office rooms is 479 CFU/m3 and it was found slightly lower compared to maximum exposure limit 500 CFU/m3. The airborne microbe levels were found slightly lower in the accommodation, training and exhibition rooms compared to office room. These findings indicate that although a new constructed building should be having a significant background level of airborne microbe (total bacteria and total fungi).
    Matched MeSH terms: Air Conditioning; Air Pollutants; Air Pollution, Indoor
  5. Razak NA, Osman NA, Gholizadeh H, Ali S
    Biomed Eng Online, 2014;13:108.
    PMID: 25085005 DOI: 10.1186/1475-925X-13-108
    The interface pressure between the residual limb and prosthetic socket has a significant effect on an amputee's satisfaction and comfort. This paper presents the design and performance of a new prosthetic socket that uses an air splint system.
    Matched MeSH terms: Air*
  6. Hashim SM, Mohamed AR, Bhatia S
    Adv Colloid Interface Sci, 2010 Oct 15;160(1-2):88-100.
    PMID: 20813344 DOI: 10.1016/j.cis.2010.07.007
    There has been tremendous progress in membrane technology for gas separation, in particular oxygen separation from air in the last 20 years. It provides an alternative route to the existing conventional separation processes such as cryogenic distillation and pressure swing adsorption as well as cheaper production of oxygen with high purity. This review presents the recent advances of ceramic membranes for the separation of oxygen from air at high temperature. It covers the issues and problems with respect to the selectivity and separation performance. The paper also presents different approaches applied to overcome these challenges. The future directions of ceramic-based membranes for oxygen separation from air are also presented.
    Matched MeSH terms: Air/analysis*
  7. Md Yusof NF, Ramli NA, Yahaya AS, Sansuddin N, Ghazali NA, Al Madhoun W
    Environ Monit Assess, 2010 Apr;163(1-4):655-67.
    PMID: 19365611 DOI: 10.1007/s10661-009-0866-0
    There are many factors that influence PM(10) concentration in the atmosphere. This paper will look at the PM(10) concentration in relation with the wet season (north east monsoon) and dry season (south west monsoon) in Seberang Perai, Malaysia from the year 2000 to 2004. It is expected that PM(10) will reach the peak during south west monsoon as the weather during this season becomes dry and this study has proved that the highest PM(10) concentrations in 2000 to 2004 were recorded in this monsoon. Two probability distributions using Weibull and lognormal were used to model the PM(10) concentration. The best model used for prediction was selected based on performance indicators. Lognormal distribution represents the data better than Weibull distribution model for 2000, 2001, and 2002. However, for 2003 and 2004, Weibull distribution represents better than the lognormal distribution. The proposed distributions were successfully used for estimation of exceedences and predicting the return periods of the sequence year.
    Matched MeSH terms: Air Pollutants/analysis
  8. Bhatia S, Abdullah AZ, Wong CT
    J Hazard Mater, 2009 Apr 15;163(1):73-81.
    PMID: 18649998 DOI: 10.1016/j.jhazmat.2008.06.055
    Adsorption behaviours of butyl acetate in air have been studied over silver-loaded Y (Si/Al=40) and ZSM-5 (Si/Al=140) zeolites. The silver metal was loaded into the zeolites by ion exchange (IE) and impregnation (IM) methods. The adsorption study was mainly conducted at a gas hourly space velocity (GHSV) of 13,000 h(-1) with the organic concentration of 1000 ppm while the desorption step was carried out at a GHSV of 5000 h(-1). The impregnated silver-loaded adsorbents showed lower uptake capacity and shorter breakthrough time by about 10 min, attributed to changes in the pore characteristics and available surface for adsorption. Silver exchanged Y (AgY(IE)) with lower hydrophobicity showed higher uptake capacity of up to 35%, longer adsorbent service time and easier desorption compared to AgZSM-5(IE). The presence of water vapour in the feed suppressed the butyl acetate adsorption of AgY(IE) by 42% due to the competitive adsorption of water on the surface and the effect was more pronounced at lower GHSV. Conversely, the adsorption capacity of AgZSM-5(IE) was minimally affected, attributed to the higher hydrophobicity of the material. A mathematical model is proposed to simulate the adsorption behaviour of butyl acetate over AgY(IE) and AgZSM-5(IE). The model parameters were successfully evaluated and used to accurately predict the breakthrough curves under various process conditions with root square mean errors of between 0.05 and 0.07.
    Matched MeSH terms: Air*
  9. Med J Malaysia, 1974 Dec;29(2):109-10.
    PMID: 4282394
    Matched MeSH terms: Air Pollution/prevention & control
  10. Lesaca RM
    Med J Malaysia, 1974 Dec;29(2):102-6.
    PMID: 4282392
    Matched MeSH terms: Air Pollution/prevention & control
  11. Yamaguchi M
    Med J Malaysia, 1974 Dec;29(2):114-24.
    PMID: 4282396
    Matched MeSH terms: Air Pollution/prevention & control
  12. Park K
    Med J Malaysia, 1974 Dec;29(2):111-4.
    PMID: 4282395
    Matched MeSH terms: Air Pollution/prevention & control
  13. Abdullah S, Mansor AA, Napi NNLM, Mansor WNW, Ahmed AN, Ismail M, et al.
    Sci Total Environ, 2020 Aug 10;729:139022.
    PMID: 32353722 DOI: 10.1016/j.scitotenv.2020.139022
    An outbreak of respiratory illness which is proven to be infected by a 2019 novel coronavirus (2019-nCoV) officially named as Coronavirus Disease 2019 (COVID-19) was first detected in Wuhan, China and has spread rapidly in other parts of China as well as other countries around the world, including Malaysia. The first case in Malaysia was identified on 25 January 2020 and the number of cases continue to rise since March 2020. Therefore, 2020 Malaysia Movement Control Order (MCO) was implemented with the aim to isolate the source of the COVID-19 outbreak. As a result, there were fewer number of motor vehicles on the road and the operation of industries was suspended, ergo reducing emissions of hazardous air pollutants in the atmosphere. We had acquired the Air Pollutant Index (API) data from the Department of Environment Malaysia on hourly basis before and during the MCO with the aim to track the changes of fine particulate matter (PM2.5) at 68 air quality monitoring stations. It was found that the PM2.5 concentrations showed a high reduction of up to 58.4% during the MCO. Several red zone areas (>41 confirmed COVID-19 cases) had also reduced of up to 28.3% in the PM2.5 concentrations variation. The reduction did not solely depend on MCO, thus the researchers suggest a further study considering the influencing factors that need to be adhered to in the future.
    Matched MeSH terms: Air Pollution*
  14. Sasnila Pakpahan, Bambang Wispriyono, Budi Hartono, Juliana Jalaludin
    MyJurnal
    Introduction: School environment represents an important microenvironment for students who spend 6-8 hours in classrooms. Indoor air quality is linked to several respiratory diseases in the school age group. This research aims to study indoor air quality of schools at different environmental characteristic and assess its health risks to students. Methods: This research measured air quality (PM2.5, PM10, CO2 , and HCHO) in three junior high schools and followed by health risk assessment. Results: This research found that the mean or median level of indoor PM2.5 and PM10 in all three schools exceeded the standard value with health risks (HQ> 1) for PM2.5 in all three schools and PM10 in two schools. Whereas carbon dioxide and formaldehyde concentrations were still safe and did not inflict health risks (HQ < 1). The scenario for managing the health risk of PM2.5 and PM10 exposure was to control the exposure at a safe threshold of PM2.5 0.035 mg/m3 ; 0.043 mg/m3 and PM10 0.144 mg/m3 for most of the population at normal school time. Conclusion: It was concluded that the level of indoor particulate matters indicates poor indoor air quality in all three schools at different environmental characteristic and inflicts health risk on students so that the health risk management is required.
    Matched MeSH terms: Air Pollution; Air Pollution, Indoor
  15. Salamone F, Belussi L, Danza L, Galanos T, Ghellere M, Meroni I
    Sensors (Basel), 2017 May 04;17(5).
    PMID: 28471398 DOI: 10.3390/s17051021
    The article describes the results of the project "open source smart lamp" aimed at designing and developing a smart object able to manage and control the indoor environmental quality (IEQ) of the built environment. A first version of this smart object, built following a do-it-yourself (DIY) approach using a microcontroller, an integrated temperature and relative humidity sensor, and techniques of additive manufacturing, allows the adjustment of the indoor thermal comfort quality (ICQ), by interacting directly with the air conditioner. As is well known, the IEQ is a holistic concept including indoor air quality (IAQ), indoor lighting quality (ILQ) and acoustic comfort, besides thermal comfort. The upgrade of the smart lamp bridges the gap of the first version of the device providing the possibility of interaction with the air exchange unit and lighting system in order to get an overview of the potential of a nearable device in the management of the IEQ. The upgraded version was tested in a real office equipped with mechanical ventilation and an air conditioning system. This office was occupied by four workers. The experiment is compared with a baseline scenario and the results show how the application of the nearable device effectively optimizes both IAQ and ILQ.
    Matched MeSH terms: Air Conditioning; Air Pollution, Indoor
  16. Thiruchelvam L, Dass SC, Zaki R, Yahya A, Asirvadam VS
    Geospat Health, 2018 05 07;13(1):613.
    PMID: 29772882 DOI: 10.4081/gh.2018.613
    This study investigated the potential relationship between dengue cases and air quality - as measured by the Air Pollution Index (API) for five zones in the state of Selangor, Malaysia. Dengue case patterns can be learned using prediction models based on feedback (lagged terms). However, the question whether air quality affects dengue cases is still not thoroughly investigated based on such feedback models. This work developed dengue prediction models using the autoregressive integrated moving average (ARIMA) and ARIMA with an exogeneous variable (ARIMAX) time series methodologies with API as the exogeneous variable. The Box Jenkins approach based on maximum likelihood was used for analysis as it gives effective model estimates and prediction. Three stages of model comparison were carried out for each zone: first with ARIMA models without API, then ARIMAX models with API data from the API station for that zone and finally, ARIMAX models with API data from the zone and spatially neighbouring zones. Bayesian Information Criterion (BIC) gives goodness-of-fit versus parsimony comparisons between all elicited models. Our study found that ARIMA models, with the lowest BIC value, outperformed the rest in all five zones. The BIC values for the zone of Kuala Selangor were -800.66, -796.22, and -790.5229, respectively, for ARIMA only, ARIMAX with single API component and ARIMAX with API components from its zone and spatially neighbouring zones. Therefore, we concluded that API levels, either temporally for each zone or spatio- temporally based on neighbouring zones, do not have a significant effect on dengue cases.
    Matched MeSH terms: Air Pollutants/analysis*
  17. Wijedasa LS, Sloan S, Page SE, Clements GR, Lupascu M, Evans TA
    Glob Chang Biol, 2018 10;24(10):4598-4613.
    PMID: 29855120 DOI: 10.1111/gcb.14340
    Carbon emissions from drained peatlands converted to agriculture in South-East Asia (i.e., Peninsular Malaysia, Sumatra and Borneo) are globally significant and increasing. Here, we map the growth of South-East Asian peatland agriculture and estimate CO2 emissions due to peat drainage in relation to official land-use plans with a focus on the reducing emissions from deforestation and degradation (REDD+)-related Indonesian moratorium on granting new concession licences for industrial agriculture and logging. We find that, prior to 2010, 35% of South-East Asian peatlands had been converted to agriculture, principally by smallholder farmers (15% of original peat extent) and industrial oil palm plantations (14%). These conversions resulted in 1.46-6.43 GtCO2 of emissions between 1990 and 2010. This legacy of historical clearances on deep-peat areas will contribute 51% (4.43-11.45 GtCO2 ) of projected future peatland CO2 emissions over the period 2010-2130. In Indonesia, which hosts most of the region's peatland and where concession maps are publicly available, 70% of peatland conversion to agriculture occurred outside of known concessions for industrial plantation development, with smallholders accounting for 60% and industrial oil palm accounting for 34%. Of the remaining Indonesian peat swamp forest (PSF), 45% is not protected, and its conversion would amount to CO2 emissions equivalent to 0.7%-2.3% (5.14-14.93 Gt) of global fossil fuel and cement emissions released between 1990 and 2010. Of the peatland extent included in the moratorium, 48% was no longer forested, and of the PSF included, 40%-48% is likely to be affected by drainage impacts from agricultural areas and will emit CO2 over time. We suggest that recent legislation and policy in Indonesia could provide a means of meaningful emission reductions if focused on revised land-use planning, PSF conservation both inside and outside agricultural concessions, and the development of agricultural practices based on rehabilitating peatland hydrological function.
    Matched MeSH terms: Air Pollutants*
  18. Shoffian Amin Jaafar, Suhaily Amran, Mohd Norhafsham Maghpor, Ahmad Sayuti Zainal, Nurzuhairah Jamil, Naemah Tajul Arus, et al.
    MyJurnal
    Indoor air quality is a term which refers to the air quality in and around buildings and structures, in which it
    is related to the health and comfort of those who are in the building. The study aims to identify the relationship
    between environmental factors with microbe growth by investigating the concentration of airborne bacteria and
    fungi at National Institute of Occupational Safety and Health (NIOSH) and to determine whether indoor bacteria and
    fungi concentration were associated with environmental factors such as temperature relative humidity and carbon
    dioxide concentration. This research was conducted concurrently with indoor air quality sampling as per requirement
    under the Malaysian Code of Practice of Indoor Air Quality (COP IAQ). The COP IAQ requires minimum of one
    sample to be taken from each area. If an area consists of a few separated rooms, each room is sampled and measured
    independently. Also this approach was used to determine whether there is a difference of indoor bacteria and fungi
    in different microenvironments. Results show that there is a significant correlation between humidity and bacteria
    concentration and fungi concentration; and between temperature and bacteria concentration. However, there is no
    significant correlation between temperature and fungi concentration. This study has also established significant
    difference on bacteria concentration and fungi concentration between microenvironments.
    Matched MeSH terms: Air Pollution; Air Pollution, Indoor
  19. Sakai N, Yamamoto S, Matsui Y, Khan MF, Latif MT, Ali Mohd M, et al.
    Sci Total Environ, 2017 May 15;586:1279-1286.
    PMID: 28236484 DOI: 10.1016/j.scitotenv.2017.02.139
    Volatile Organic Compounds (VOCs) in indoor air were investigated at 39 private residences in Selangor State, Malaysia to characterize the indoor air quality and to identify pollution sources. Twenty-two VOCs including isomers (14 aldehydes, 5 aromatic hydrocarbons, acetone, trichloroethylene and tetrachloroethylene) were collected by 2 passive samplers for 24h and quantitated using high performance liquid chromatography and gas chromatography mass spectrometry. Source profiling based on benzene/toluene ratio as well as statistical analysis (cluster analysis, bivariate correlation analysis and principal component analysis) was performed to identify pollution sources of the detected VOCs. The VOCs concentrations were compared with regulatory limits of air quality guidelines in WHO/EU, the US, Canada and Japan to clarify the potential health risks to the residents. The 39 residences were classified into 2 groups and 2 ungrouped residences based on the dendrogram in the cluster analysis. Group 1 (n=30) had mainly toluene (6.87±2.19μg/m3), formaldehyde (16.0±10.1μg/m3), acetaldehyde (5.35±4.57μg/m3) and acetone (11.1±5.95μg/m3) at background levels. Group 2 (n=7) had significantly high values of formaldehyde (99.3±10.7μg/m3) and acetone (35.8±12.6μg/m3), and a tendency to have higher values of acetaldehyde (23.7±13.5μg/m3), butyraldehyde (3.35±0.41μg/m3) and isovaleraldehyde (2.30±0.39μg/m3). The 2 ungrouped residences showed particularly high concentrations of BTX (benzene, toluene and xylene: 235μg/m3 in total) or acetone (133μg/m3). The geometric mean value of formaldehyde (19.2μg/m3) exceeded an 8-hour regulatory limit in Canada (9μg/m3), while those in other compounds did not exceed any regulatory limits, although a few residences exceeded at least one regulatory limit of benzene or acetaldehyde. Thus, the VOCs in the private residences were effectively characterized from the limited number of monitoring, and the potential health risks of the VOCs exposure, particularly formaldehyde, should be considered in the study area.
    Matched MeSH terms: Air Pollution, Indoor/analysis*
  20. Jabal MH, Abdulmunem AR, Abd HS
    J Air Waste Manag Assoc, 2019 01;69(1):109-118.
    PMID: 30215577 DOI: 10.1080/10962247.2018.1523070
    Plant (vegetable) oil has been evaluated as a substitute for mineral oil-based lubricants because of its natural and environmentally friendly characteristics. Availability of vegetable oil makes it a renewable source of bio-oils. Additionally, vegetable oil-based lubricants have shown potential for reducing hydrocarbon and carbon dioxide (CO2) emissions when utilized in internal combustion (IC) engines and industrial operations. In this study, sunflower oil was investigated to study its lubricant characteristics under different loads using the four-ball tribometer and the exhaust emissions were tested using a four-stroke, single-cylinder diesel engine. All experimental works conformed to American Society for Testing and Materials standard (ASTM D4172-B). Under low loads, sunflower oil showed adequate tribological characteristics (antifriction and antiwear) compared with petroleum oil samples. The results also demonstrated that the sunflower oil-based lubricant was more effective in reducing the emission levels of carbon monoxide (CO), CO2, and hydrocarbons under different test conditions. Therefore, sunflower oil has the potential to be used as lubricant of mating components.Implications: An experimental investigation of the characteristics of nonedible sunflower oil tribological behaviors and potential as a renewable source for biofluids alternative to the petroleum oils was carried out. The level of emissions of a four-stroke, single-cylinder diesel engine using sunflower oil as a biolubricant was evaluated.
    Matched MeSH terms: Air Pollutants/analysis*
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